Movement detection and construction of an "actual reality" image

Abstract

A method for intraframe image compression of an image is combined with a method for reducing memory requirements for an interframe image compression. The intraframe image compression includes (a) dividing the image into blocks; (b) selecting a block according to a predetermined sequence; and (c) processing each selected block by: (1) identifying a reference block from previously processed blocks in the image according to an activity metric; and (2) using the reference block, compressing the selected block. The selected block may be compressed by compressing a difference between the selected block and the reference block, where the difference may be offset by a predetermined value. The difference is compressed after determining that an activity metric of the difference block. The activity metric depends on elements of a difference block, which is a block in which elements are each a difference between an element of the current image frame and a corresponding element of the reference frame. The activity metric is a function of the sum of (a) the sum over all rows of all differences between two successive consecutive elements of each row of the difference block; and (b) the sum over all columns of all differences between two consecutive elements of each column of the difference block. The reference block is identified by minimizing a cost function based on the activity metric and either a sum of absolute differences function or a sum of square differences function. The cost function may be a weighted sum of the activity metric and either a sum of absolute differences function or a sum of square differences function, or a weighted sum of the activity function and either a sum of absolute differences function or a sum of square differences function.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]The present application is a continuation-in-part application of U.S. patent application (“Copending application”), entitled “Movement Detection AND Construction of an ‘Actual Reality’ Image” Ser. No. 11 / 562,926 and filed on Nov. 22, 2006. The Copending applications is hereby incorporated by reference in their entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to swallowable capsule cameras for imaging of the gastro-intestinal (GI) tract. In particular, the present invention relates to data compression methods that are suitable for capsule camera applications.[0004]2. Discussion of the Related Art[0005]Devices for imaging body cavities or passages in vivo are known in the art and include endoscopes and autonomous encapsulated cameras. Endoscopes are flexible or rigid tubes that are passed into the body through an orifice or surgical opening, typically into the esophagus via the mouth or...

AI Technical Summary

Benefits of technology

[0016]According to one embodiment of the present invention, a method for intraframe image compression identify a reference block by minimizing a cost function which depends on an activity metric. The intraframe image compression includes (a) dividing the image into blocks; (b) selecting a block according to a predetermined sequence; and (c) processing each selected block by: (1) identifying a reference block from previously processed blocks in the image according to an activity metric; and (2) using the reference block, compressing the selected block. The selected block may be compressed by compressing a difference between the selected block and the reference block, where the difference may be offset by a predetermined value. The activity metric depends on elements of a difference block, which is a block in which elements are each a difference between an element of the current image frame and a corresponding element of the reference frame.

[0017]According to one embodiment of the present invention, the activity metric is a function of the sum of (a) the sum over all rows of all differences between two successive consecutive elements of each row of the difference block; and (b) the sum over all columns of all differences between two consecutive elements of each column of the difference block. The reference block is identified by minimizing a cost function based on the activity metric and either a sum of absolute differences function or a sum of square differences function. The cost function may be a weighted sum of the activity metric and either a sum of absolute differences function or a sum of square differences function, or a weighted sum of the activity function and either a sum of absolute differences function or a sum of square differences function.

Problems solved by technology

However, they have a number of limitations, present risks to the patient, are invasive and uncomfortable for the patient.

The cost of these procedures restricts their application as routine health-screening tools.

Because of the difficulty traversing a convoluted passage, endoscopes cannot reach the majority of the small intestine and special techniques and precautions, that add cost, are required to reach the entirety of the colon.

Endoscopic risks include the possible perforation of the bodily organs traversed and complications arising from anesthesia.

Moreover, a trade-off must be made between patient pain during the procedure and the health risks and post-procedural down time associated with anesthesia.

Endoscopies are necessarily inpatient services that involve a significant amount of time from clinicians and thus are costly.

The capsule camera allows the GI tract from the esophagus down to the end of the small intestine to be imaged in its entirety, although it is not optimized to detect anomalies in the stomach.

The cost of the procedure is less than for traditional endoscopy due to the decreased use of clinician time and clinic facilities and the absence of anesthesia.

However, these methods all require a physical media conversion during the data transfer process.

When images are transmitted over a wireless link, the vast amount of data transmitted over many hours of capturing images as the capsule travel through the body severely tax battery power.

Also, in the prior art, the bandwidth required for the transmitting image data at the desired data rate easily exceeds the limited bandwidth allocated by the regulatory agency (e.g., Federal Communication Commission) for medical applications.

Alternatively, when an on-board storage is provided in the capsule camera, the uncompressed image files can easily require multiple gigabytes of storage, which is difficult to provide in a capsule camera.

At the same time, examining the large number of images captured by a capsule camera (e.g., 50,000 images for an adult small intestine and over 150,000 for an adult large intestine) is very time consuming.

Low patient through-put and high cost result.

Because many of the images overlap each other by substantial portions, as the physician goes over these repetitive areas, there is the risk of overlooking a significant area which otherwise should be examined.

The large amount of data to examine prohibits the use of telemedicine, and even archiving and data retrieval are difficult.

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